原位合成含钛陶瓷相增强Fe基合金熔覆层研究

以Fe901、Ti、B_4C和h-BN粉为原料,采用反应等离子熔覆方法在Q235钢基本上原位合成了含钛陶瓷相增强Fe基合金熔覆层。研究表明:相比B_4C,Fe更易与h-BN反应形成铁硼化物,当同时添加B_4C和h-BN时,B_4C/h-BN比减小至一定值后将导致熔覆层中Fe B含量升高和Ti_2N、Ti B等中间产物形成,但却可抑制陶瓷相长大。熔覆层显微组织均具有梯度分布特征,Ti B_2大小和形态受熔池温度和成分影响。熔覆层显微硬度随h-BN添加量增加而降低,Ti:B_4C:BN摩尔比为3:1:0时熔覆层近表面层HV_(0.2)显微硬度可高达11.26 GPa。

Research on the Fe-based alloy clad coatings reinforced by in situ synthesized ceramic phases containing titanium

The Fe-based alloy coatings reinforced with in situ synthesized ceramic phases containing titanium were prepared on Q235 steel by reactive plasma cladding process using Fe901, Ti, B4C and h-BN powders as raw materials. The results show that Fe is apt to react with h-BN to produce FeB comparing with B4C. If both of B4C and BN are added as reactants, the content of FeB will increase and the Ti2N and TiB intermediates can be found in the coatings when B4C/h-BN ratio decreases to a certain value. However, it can depress the growth of ceramic phases. The microstructure of the clad coatings exhibits an obvious gradient distribution along the depth direction. The size and morphology of TiB2 change with the temperature and composition of the molten pool. Increasing h-BN amount will result in the decrease of microhardness of the coatings. The high microhardness value 1126HV0.2 can be achieved at the near surface layer for the coating at Ti : B4C : h-BN=3 : 1 : 0.